Steel roll



Dec. 1, 1959 J. A. PLACE ETAL 2,914,906

YARN AND ITS MANUFACTURE Filed Jan. 24. 1956 STEEL ROLL BALLOON GUIDE INVENTORS' JAMES ALFRED PLACE WLYM GARROD THOMA$ GERALD ALFRED WHITE BY (AW 9M1 MM 1 ATTORNEY:

i d t tes a n YARN AND ITS MANUFACTURE James Alfred .Place, West :Pontnewydd, .Cwmbran,

Gwilym Gan-0d Thomas, .Pontypool .and .Gerald Alfred White, Croesyceiliog, .Cwmhran, England, assignors to British Nylon Spinners Limited, Pontypool, Great Britain, a corporation :of Great Britain Application January 2-4, 1956,"SerialtNo. 55 61,143

fizClaims. c1. 51- -1s7 This invention relates to yarn com-prising synthetic linear polymers, and more particularly to yarn consisting of or containing a synthetic linear polyamide, and to processes for manufacturing said yarn.

The present yarn consists, at least mainly, of a synthetic linear polymer, ;-for example, ,a polyamide or a polyester, and ;is characterised hy-nouel anduseful properties. By the expression yarn there are to'be understood also to be included thread, cord, braid, doubled yarn, looped yarn and the like. v

During the last decade ,the employment of synthetic linear pol ymer yarn, notably polyamide yarn and'later polyester yarn, in various textile fields formerly depending on .natural fibres :or conventional rayon yarn, such as viscose :or cellulose .acetate, has continuously :increased. Yarn-composed of :a :synthetic linearpolymer possesses numerous excellent :properties among which high tenacity, resistance to abrasion and uniformity .are especially to be reckoned. Neverthelesssuch yarn is apt to be regarded, inthe caseof some .enduses, ,as inadequate or capable of improvement in respect of aquality known as handle, .feel, loftiness :or fullness, .a charac teristic which is not :easy:to define because it .,is,'largely subjective and consequently a matter of personal opinion. The reason for the lack of fullness seems to reside ,at least in some measure in .the normal smoothness of synthetic linear polymerfilaments. Be this as it may, however, this ,qualityof fullness is of .g reatjmportance because it is understood be related to the power .of fabrics made ,from the yarn ,to @absorb moisture and afford warmth. Consequently efforts have ,frequently been made in the past, to enhance the fullness of synthetic linear polymer yarn, by increasing its bulk by means of numerous crimpingprocesses or by giving it a hairy or-fuzzynature invarious ways. Yet itis difli cult to obtain quite the desired effect. For 'not only must the yarn *presentithe right appearance" to the ;eye and possess the correct *feel,"but it is essential that .it have the necessary mechanical properties as well. For example, a-crimped yarnof suitable fullness and appear.- ance, may lose these qualities on being "woven owing to the tension exerted in theloom pulling out the 'crirnps. Hot wet treatment as, for instance, in dyeing, is also liable to interfere withfthe'physical nature of" the ;yarn.

The presentinvention concerns a I16W "PIOCSS .for producing a full or lofty synthetic 'linear polymer yarn, which depends0n the intermittent separation of short lengths of-in'dividual ifilaments :'from the main 'strand'of a multifilament yarn, the separated 'fil'aments being looped, curled jor'con'voluted so ;asto1projectfrom the main strand. 'The aforesaid separation 'andloopingof the filaments is brought about by applying to a running synthetic linear polymer 'multifilament yarn of.no or low twist a shearing stressfby passing the yarn between two surfaces which bear resiliently thereupon, and .are in relative motion in the direction of the a x isaof the yarn where "they make .contact therewith. These surfaces may be plane or curved. One or both of said surfaces may be constituted by the periphery of a roll. For example, the yarn may passunder pressure between a motionless support and a rapidly revolving roll, the peripheral speed of which is, say, perhaps, six or seven times that of the yarn, and in the same direction as the yarn is proceeding at the point of contact therewith. Or else the yarn may pass between two rolls revolving in opposite directions, the nip thus occasioned produci-ng the necessary shearing stress referred to above. After passingthe nip the yarnexhibits numerous small loops 'or curls of filament projecting from the main strand. Experiment shows that the nature of the moving surfaces, by which is meant their degree of smoothness, hardness and coefficient of friction has an important bearing on the quality of the yarn produced. The pressure exerted between the surfaces also needs to be carefully-adjusted. The foregoing factors seem to influence the way in which, and degree to which, the individual filamen-ts are, as it were, snatched from the main running strand and bent back or curled away. However, it is emphasised that the operation of this part of the invention is not precisely understood. After the individual filaments have beenthus separated, the Whole yarn is then twisted or furthertwisted, the tension being preferably maintained during this twisting at a low value.

Accordingly this invention relates to a process for the manufacture-of-yarn comprising passing a running multifilament yarn of no or low :twist, consisting at least mainly of aesyntheticlinear polymer, between two surfaces, which-are themselves .in relative motion, at least a component t-hereof being parallel to the axis of the running-yarn, and .which'bear resiliently thereon, so as to effect intermittent separation of random short lengths of individual filaments from the main strand of yarn, and thereupon twisting or further twisting the Whole yarn, preferably-while it is maintained under a low degree of tension.

The invention includes yarns consisting atleast mainly of --synthetic linear polymers, which yarns have been made by the above process.

'The synthetic linearpolymer of which the yarn is mademay consist, for instance, wholly ofpolyhexamethylene-adipamide,-but other polymers may form the material of the yarn, for instance, polyureas, polyurethanes, polyaminotriazoles, polyesters, e.g. polyethylene glycol terephthalate, or the following ,polyamides, namely, polyhexamet-hylene sebacamide, polypentarnethylene sebacam'ide, -polytetramethylene adipamide, polyocta methylene adipamide,polydecarnethylene adipamide and polycaprolactam. The yarn of the presentinventionmay include other material besides synthetic linear polymers provided that the latter :form atleast the major proportiOn of ,said yarn. For v,exarnple there may be intermingled ;filaments or fibresof wool, ,cotton, cellulose acetate,.viscose or polyvinyl chloride.

,That'the twist of themultifilament :yarn should be low has alreadybeen indicated. While upto 10 turns per inch maybe regarded as admissible, the number of turns is advantageously below '6per inch. ;From toSiturns per inch. are found to be satisfactory. i

The moving surfacesmay consist of two pads, as it were, vruhbingto and fro on either side of the yarn. The direction of rub may form an angle with the axis of the running yarn, provided there is, as already indicated, a component of motion parallel to the axis of the yarn, nor need the surfaces be continuously in movement. Or else in'place-of moving pads, two revolvingdiscs might constitute the moving surfaces. It is, however, preferred that at least one of the two moving surfaces should take ei r nlo a, r i g. o sma frotn themechmica convenience of a roll, it tends to combat wear, due to abrasion by the running yarn, since it provides a larger surface. If two rolls are installed, one or both may be in motion, so long as the relative movement is present. The material of these surfaces should be chosen so as to withstand abrasion as far as possible, while yet gripping the filaments. Suitable materials are glass, ceramics, vulcanite, alumina, titania, Carborundum, rubber, agate and stainless steel. The pressure between the surfaces is conveniently applied by means of a spring, or springs, which should be capable of adjustment. The latter adjustment can be achieved with the aid of an arbitrary scale indicating the pressure, but it is frequently found that good results are obtainable over a fairly wide range of pressures, provided the surfaces are not too hard or rough.

The twist imparted to the yarn coming from the moving surfaces may be, for example, 3-20 turns per inch, but it will be understood that the quality of the yarn depends on the interrelation between this twist, the rate of passage of the yarn between the moving surfaces, and the rate of relative movement of the latter. The hardness and roughness of the surfaces are also significant factors in determining the nature or handle of the resultant yarn. The required twist, e.g., 10 turns per inch, may be conventionally produced by winding the yarn downwards over end on to a vertical bottle bobbin, but since a low tension is preferred, it is advantageous to use light travellers. Alternatively it is possible to pass the yarn, before it is wound on to the bobbin, through a false twisting device, revolving in the same direction as the bobbin and placed above the spindle thereof or through some other form of tension barrier e.g. a gate tensioner. By this means the tension of the yarn undergoing twisting may be reduced to a very low figure, particularly if the false twisting device revolves at the same speed as the bobbin. The quality of the yarn is thus affected by the relative speed of the false twisting device as compared with that of the bobbin.

One embodiment of the invention is illustrated in the accompanying drawing wherein the yarn 1 is forwarded from the supply package 2 by passage between a cork roll 3 and a steel roll 4. From the said rolls 3 and 4 the yarn passes to the moving surfaces which comprise a rotating stainless steel roll 5 against which a titania rod 6 is urged by means of the spring-loaded arm 7. Thence the yarn proceeds to a conventional wind-up bobbin 8, the effect of the ring traveller 9 thereof being to twist the yarn. The pig-tail yarn guides are numbered 10.

The yarns of the present invention may be, if desired, subsequently doubled, braided, looped, steam-set, dyed, sized or otherwise conventionally treated to prepare them for use in knitting, warp-knitting, weaving or other textile manufacturing process.

The following examples are intended to illustrate but not limit the invention.

Example 1 A 34-filament yarn of polyhexamethylene adipamide having a denier of 70 and turn per inch Z twist is fed between rolls at 50 feet per minute. Thence the yarn passes between a titania rod and a stainless steel roll. The titania rod is caused to bear resiliently against the yarn and the roll by means of a spring. The roll revolves at a peripheral speed (in the direction of movement of the yarn) of 350 feet per minute. From the roll the yarn. runs down to a false twist device, round the pivot of whichv it is wrapped once, and from there it passes via a pig-tail. on to a bobbin rotating at 3600 revolutions per minute toirnpart a Z twist. The false twist device also rotates at 3600 revolutions per minute.

The resulting yarn has a pleasant full handle and can; be woven into soft warm cloth.

ExampleZ .A 34-filament yarn of polyhexamethylene adipamide,

having a denier of 100 and /4 turn per inch 2 twist is passed between feed rolls at 65 feet per minute. The yarn then proceeds between a sintered alumina pin of ,4 diameter and a synthetic rubber roll having a peripheral speed of 700 feet per minute. The pin bears on the roll with a force of 28 ounces. After passing through a gate tensioner, the yarn is wound on a bobbin with a No. 21 traveller (0.0048 oz.), the spindle speed being 3600 revolutions per minute. The resulting yarn is very fuzzy. When woven as weft with untreated yarn as warp, a fabric having a full and pleasant feel is obtained.

Example 3 Example 2 is repeated except the feed roll speed is 50 feet per minute, the rubber roll peripheral speed 200 feet per minute, the bobbin speed 6500 revolutions per minute and the traveller No. 23 (0.0040 02.). Moreover instead of the gate tensioner, the yarn leaving the rubber roll traverses a false twist head revolving 5000 times per minute. The denier of the yarn is found to have increased by 22%.

Example 4 Example 2 is repeated, the gate tensioner being replaced by a stationary rubber tube through which the yarn passes. The speeds are:

Feed rolls 55 feet per minute.

Rubber roll 550 feet per minute.

Forceof pin on roll 0.7 ounce. Wind up bobbin 6500 revolutions per minute.

' yarn entering the said tube.

Polyhexamethylene adipamide yarn having 50 fila- I ments of 3 denier each twisted to 2% 2 turns per inch is passed through feed rolls at 50 feet per minute and thence between a sintered alumina pin of A diameter on which a flat has been ground with Carborundum powder and a synthetic rubber roll having a peripheral speed of 550 feet per minute. The flat surface of the pin is pressed against the latter. On being wound up at 6500 revolutions per minute with the use of a No. 40 traveller (0.00034 ounce), the yarn exhibits a large number of small loops or convolutions, and possesses a denier of 170. Fabric woven therefrom has a warm and pleasant handle.

Example 6 Polyhexamethylene adipamide yarn of filaments (total denier 840) having 1 Z turn per inch twist is treated as in Example 5, save that a No. 20 traveller (0.0066 ounce) is employed and the alumina pin is replaced by a flat Carborundum shoe bearing tangentially on the rubber roll. The denier of the resulting yarn is 1500. It is very fuzzy and soft.

What we claim is:

1. Process for the manufacture of yarn comprising passing a running multifilament yarn of low twist, consisting at least mainly of a synthetic linear polymer, between two surfaces, which are themselves in relative motion, at least a component thereof being parallel to the axis of the running yarn, and which bear resiliently thereon, thereby separating intermittent random small loops of individual filaments from the main strand of yarn, said filaments being retained in the yarn, and thereupon twisting the whole yarn.

2. Process for the manufacture of yarn as claimed in claim 1, wherein at least one of the two surfaces is the peripheral surface of a roll.

3. Process for the manufacture of yarn as claimed in claim 2 wherein the multifilament yarn of low twist has no 03 9 .6 turns per inch, and the twisting or further References Cited in the file of this patent UNITED STATES PATENTS Taylor et a1 Apr. 13, 1937 Truitt Dec. 9, 1947 Storey May 13, 1952 Breen Mar. 5, 1957 

